The present invention relates to a silicone oil emulsion, a method of manufacturing of the aforementioned emulsion, and a method for the preparation of a silicone composition. More specifically, the invention concerns a silicone oil emulsion that contains cross-linked silicone particles in silicone oil drops which are dispersed in water; a method of manufacturing the aforementioned silicone oil emulsion; and a method for the preparation of a silicone composition comprising cross-linked silicone particles uniformly dispersed in a silicone oil.
A method of manufacturing cross-linked silicone particles which contain non-cross-linkable silicone oil is known. The particles are prepared by dispersing a cross-linkable silicone composition that contains the non-cross-linkable silicone oil in water and causing a cross-linking reaction, i.e. Japanese Laid-Open Patent Application Kokai Sho 01-81856 and Hei 2-243612 (U.S. Pat. No. 4,980,167). This method, however, does not allow the obtaining of a silicone oil emulsion which would contain cross-linked silicone particles in silicone oil drops dispersed in water.
A method for the preparation of a silicone oil emulsion which contains cross-linked silicone particles dispersed in it and drops of silicone oil in water is also known. This method comprises combining cross-linked silicone particles with a silicone oil emulsion containing silicone oil drops dispersed in water, i.e. Japanese Laid-Open Patent Application Kokai Hei 3-271211 and Hei 9-53047 (U.S. Pat. No. 5,760,109). In this method, however, silicone oil drops and cross-linked silicone particles are dispersed in water independently, and therefore this method is not suitable for the preparation of silicone oil emulsions that would contain cross-linked silicone particles in the silicone oil drops.
Furthermore, known in the art are silicone compositions comprising cross-linked silicone particles dispersed in silicone oil, i.e., Japanese Laid-Open Patent Applications Kokai Sho 63-152308, Hei 1-165509, Hei 1-207354, Hei 2-43263 (U.S. Pat. No. 4,987,169), Hei 6-502646 (U.S. Pat. No. 5,1548,49) and Hei 7-330537. The silicone compositions can be prepared by mixing a silicone oil with cross-linked silicone particles, or by treating the product of cross-linking of a cross-linkable silicone composition, which contains non-cross-linkable silicone oil, with shearing forces, i.e., Japanese Laid-Open Patent Application Hei 2-43263. However, in silicone compositions prepared by the above methods, cross-linked silicone particles are dispersed in silicone oil nonuniformly, and therefore they cannot demonstrate their specific properties sufficiently.